Simplify identifier() by always quoting.

Previously we only quoted when it had to be.

src/pg8000/converters.py

@@ -772,33 +772,18 @@ def make_params(py_types, values):
     return tuple([make_param(py_types, v) for v in values])
 
 
-def _quote_letter(c):
-    return c.isupper() if c.isalpha() else True
-
-
 def identifier(sql):
     if not isinstance(sql, str):
         raise InterfaceError("identifier must be a str")
 
     if len(sql) == 0:
         raise InterfaceError("identifier must be > 0 characters in length")
 
-    quote = _quote_letter(sql[0])
+    if "\u0000" in sql:
+        raise InterfaceError("identifier cannot contain the code zero character")
 
-    for c in sql[1:]:
-        if _quote_letter(c) and c not in "0123456789_$":
-            if c == "\u0000":
-                raise InterfaceError(
-                    "identifier cannot contain the code zero character"
-                )
-            quote = True
-            break
-
-    if quote:
-        sql = sql.replace('"', '""')
-        return f'"{sql}"'
-    else:
-        return sql
+    sql = sql.replace('"', '""')
+    return f'"{sql}"'
 
 
 def literal(value):

test/test_converters.py

@@ -341,14 +341,14 @@ def test_identifier_quoted_null():
 @pytest.mark.parametrize(
     "value,expected",
     [
-        ("top_secret", "top_secret"),
+        ("top_secret", '"top_secret"'),
         (" Table", '" Table"'),
         ("A Table", '"A Table"'),
         ('A " Table', '"A "" Table"'),
-        ("table$", "table$"),
+        ("table$", '"table$"'),
         ("Table$", '"Table$"'),
-        ("tableఐ", "tableఐ"),  # Unicode character 0C10 which is uncased
-        ("table", "table"),
+        ("tableఐ", '"tableఐ"'),  # Unicode character 0C10 which is uncased
+        ("table", '"table"'),
         ("tAble", '"tAble"'),
     ],
 )